Refrigerating apparatus



Dec. 16, 1941. A. J. KUHN REFRIGERATING APPARATUS Filed July 30, 1940 IH-IH w/Z14, ATTORNEYS Patented Dec. 16, 1941 REFBIGERATING APPARATUS Albert J. Kuhn, Dayton, Ohio, assignor to General Motors Corporation, Dayton, Ohio, a corporation of Delaware Application July 3., 1940, Serial No. 348,409

This invention relates to refrigerating apparatus and more particularly to automatic starting means for internal combustion engine used for driving refrigerator compressors and other applications wherein automatic starting is desired.

In automatic starting systems for internal combustion engines it is desirable to provide some means for stopping the starting motor in case the engine should fall to start. I have found that the means previously used for taking care of such a situation were not altogether accurate and reliable.

It is an object of my-inventlon to provide an automatic .starting system for an internal combustion engine which is accurate and reliable.

It is another object of my invention to provide a means for accurately and reliably deenergizing the starting motor of an internal combustion engine in case the engine fails to start within a reasonable time.

It is another object of my invention to provide an improved, more reliable and more accurate electrical timing device for limiting the time allowed for the starting motor to start an internal combustion engine.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing, wherein a preferred form of the present invention is clearly shown.

In the drawing:

Fig. 1 is a wiring diagram of one form of an automatic starting system for an internal combustion engine embodying my invention;

Fig. 2 is a view in elevation of a vibrating type relay shown diagrammatically in Fig. 1; and

Fig. 3 is a wiring diagram illustrating another form of the invention.

Briefly I have shown an electrothermal timing device for limiting the energization of the starting motor of an internal combustion engine. The current operating this timing device is accurately controlled regardless of battery conditions so that the starting motor can only be energized for a predetermined length of time such as 30 seconds in case the engine fails to start. This regulation is so accomplished that in case the device fails to operate properly the time allowed will not be lengthened.

Referring now to the drawing and more particularly to Fig. 1, there is shown diagrammatically a starting motor 2! for starting an internal combustion engine through some suitable cranking device such as the Eclipse Bendix drive connected by the conductor 32 to the other terminal 34 of the battery 28.

When the engine is used to drive a refrigerant compressor, the energization of the solenoid 24 i preferably controlled by a solenoid switch 36, controlled by a high pressure switch 3| operated in response to a predetermined high condenser pressure in the refrigerating ssytem. This switch 36 is normally closed while the switch 38 is normally open. A second solenoid switch 40 is connected in series with the switch 36 and the solenoid 24 and is controlled by the thermostatic switch 42 which may be operated toenergize and close the solenoid switch 40 upon a predetermined increase in temperature. This thermostatic switch 42 may be responsive to room or interior temperature, cabinet temperature or evaporator temperature.

In the systems shown there is no means for deenergizing the starting motor 20 when starting is accomplished. If desired, some switch responsive to the operation of the engine, such as a centrifugal switch, an oil pressure switch or a manifold vacuum switch may be connected in series with the switches 36 and 40 to open the solenoid switch 22 and deenergize the starting motor. However, even if such a switch is installed it is also desirable to'provide a time limitation upon the operation of the starting motor 20 in case the motor fails to start. For this purpose I provide a switch means 44 which is operated by an electrothermal timing device connected in parallel circuit arrangement with the starting motor 20 and in series with its switch 22. The operating means for the'switch 44 may be of any electrical type but for illustrative purposes it is shown diagrammatically as a cantilever type of bimetal 48 in operative connection by means of the rod 48 with the switch 44. This bimetal 46 is energized by an electric heater 50 at such a rate that when the starting motor 20 i operated for a predetermined period such as 30 seconds,

or the Dyer drive. The internal combustion enthe bimetal 48 will move the rod 48 to operate the switch 44 to deenergize the solenoid 24 and to connect in circuit a warning device 52, such as a buzzer to indicate the failure of operation of the internal combustion engine.

In order that this timing be accurate and reliable, I have provided a regulating scheme for regulating the output of the heater under all battery conditions. To do this, I have connected a resistance 54 in series with the heater 50. In parallel with the heater 50 I have connected the solenoid 56 of a vibrating type control. The contacts operated by the armature 58 of this vibrating contact mechanism connect with the conductor 80 which is connected in parallel with the resistance 54 so as to shunt out resistance 54. A conductor 62 connects the armature 58 with the conductor connecting the heater 50 and the resistance 54.

This. type of device accurately regulates the I amount of current flowing through the heater 50 by the intermittent operation of the armature 58 which connects and disconnects from the conductor 60 so as to shunt the resistance 54 part of the time and otherwise require all the current to flow through the resistance 54. Thus by this device a measured amount of current will flow through the heater 50. This device, however, has a further advantage that in case of failure it will not increase the length of time the switch 44 remains closed. Normally, in this device, any failure would result in the sticking of the vibrating contacts so that the armature 58 would be connected to the conductor 60. This would decrease the time the starting motor 20 would be allowed to operate so that the-protective device is assured of operation under practically all operating conditions.

Fig. 2 shows a practical embodiment of one form of a vibrating contact device. The coil 56 at all times exerts a magnetic attraction upon the armature 58. This attraction is opposed by the coil spring 64 which is connected to an extension 66 of the armature 58 on the opposite side of the spring hinge 68. The downward movement of the armature 58 is limited by the stop while the upward movement is limited by the rubber stop 12. The armature 58 carries a contact I4 which is adapted to make engagement when in its upper position with the contact 16 provided upon a leaf spring I8. The outer end of the leaf spring I8 is provided with a button 80 which is adapted to normally engage the stop 82 for limiting the downward movement of the contact 16. By this arrangement a definite voltage will be maintained upon the heater by alternately energizing and shunting the resistance 54 to control the voltage and the current passing through the heater 50.

-In Fig. 3 there is shown another system which includes a battery I28 and a solenoid switch I22 for connecting the starting motor I20 to the terminals of the battery I28. 'The solenoid switch I22 is provided with the solenoid operating coil I24 under the control of suitable switches such as a pressure switch I38 and a temperature switch I42. The closing of both of these switches is required to close the switch I22 for energizing the starting motor of the internal combustion engine.

In order to stop the starting motor I20 after a predetermined period of time, such as 30 seconds, I provide a bimetal timing device including a cantilever supported bimetal member I46 which is controlled by a compression type snap acting spring I41. This bimetal I46 is connected to one terminal of the battery I28 while its free end is provided with contact means for making contact at one end of its movement with the contact I44 connected in series with the switches I38 and I42 as well as the solenoid I26.

The bimetal I46 is provided withan electric heater I50 having uniform current flowing through it regardless of the condition of the battery I28. This is insured by an electromagnetic vibrating control which includes a solenoid I58 connected in series with the heater I50. This solenoid I56 operates upon an armature I58 which, in the open position. connects to a conductor I60 shunting the resistance I54 which is otherwise connected in series with the solenoid I56 and the heater I50.

As explained in connectiton with Figs. 1 and 2 this vibrating type control I56 regulates the current passing through the heater I50 by the energizing and shunting of the resistance I54 through the operation of the electromagnetic vibrating device. However, in the form shown in Fig. 3, the solenoid I56 is connected in series with the heater I50 instead of in parallel as in Fig. 1. If the internal combustion engine should fail to start within the prescribed time, the heater III will heat the bimetal I46 sufficiently to cause the contacts at the end of the bimetal I46 to be moved with a snap action into contact with the stationary contact I5I, connecting with the signaling device I 52, such as a buzzer. This will indicate the failure of the engine to start. This device requires a manual reset and for this purpose I have provided a push button I65 which may be pushed downwardly to return the bimetal I46 to th position shown .in Fig. 3 so that the engine can again be started. This device may also be used in the form shown in Fig. 1 replacing the bimetal 46, the rod 48, and the switch 44. As described in connection with Fig. l, the failure of the electromagnetic vibrating contact device by the sticking of the contacts will only serve to shorten the time the starting motor is allowed to operate. Thus the starting motor is always protected. The electromagnetic vibrating contact device accurately controls the flow of current through the heaterI50, so that the time the starting motor is allowed to operate in case the engine fails to start is always accurately determined regardless of the condition of the battery I28. The system can be made to withstand rough usage and may be used on any sort of vehicle or almost any stationary application.

Whil the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. A starting system for an internal combustion engine comprising an electric starting motor for cranking purposes, a switch means for controlling the energization of the starting motor, an electrical timing device for deenergizing I ing the motor after a certain amount of cranking, a solenoid energized in proportion to the current flowing through said timing device, a resistance connected in series circuit relation with said solenoid and timing device, a set of vibrating contacts operatedby said solenoid for intermittently shunting said resistance to regulate the energization of the timing device, and means controlled by said timing device for indicating the deenergization of said starting motor by said switch means.

3. A starting system for an internal combustion engine comprising an electric starting motor for cranking purposes, an electrically operated switch means for controlling the energization of the starting motor, an electrical timing device for operating said electrically operated switch means after a certain amount of cranking, a solenoid energized in proportion to the current flowing through said timing device, a resistance connected in series circuit relation with said solenoid and timing device, and a set of vibrating contacts operated by said solenoid for intermittently shunting said resistance to regulate the energization of the timing device.

4. A starting system for an internal combustion engine comprising an electric starting motor for cranking purposes, an electrically operated switch means for controlling the energization of the starting motor, an electrical timing device for operating said electrically operated switch means after a certain amount of cranking, a solenoid energized in proportion to the current flowing through said timing device, a resistance connected in series circuit relation with said solenoid and timing device, a set of vibrating contacts operated by said solenoid for intermittently shunting said resistance to regulate the energization of the timing device, and a second switch means for controlling the energization of said electrically operated switch means.

ALBERT J. KUHN. 

